Our Seat Belts are sewed with double nylon thread to ensure their resistance. They are belts to attach to the head rest of your car's seat so that when the dogs moves it cant open the seat belt by clicking on it accidentaly with it's paw. law asks that the dog is secure to a place not being able to invade the drivers space or interfere with driving securely. Our seat belts are adjustable at the head rest and at the leash that attaches to the dog Harness. NEVER attach a seat belt to a collar, use a harness ALWAYS. A good Crate will always be the safer option for any dog this is for when a crate is not an option.